360 series panel with 30 Amp main double pole breaker and RCBO. Residual Current Devices (RCDs) respond to leakage of electrical current outside of the intended circuit path. When the RCD function is combined with overload and short circuit protection, the device is often referred to as an RCBO. In the USA, a device that trips on leakages of nominally 5mA and meets certain standards is called a Ground Fault Circuit Interrupter (GFCI). A device meeting the same standards but with a trip level of 30mA is called an Electrical Leakage Circuit Interrupter (ELCI). This device provides GFCI or ELCI functions and circuit protection in panel mounted breakers. NOTE: These devices are designed for 120V 60-Cycle and 120/240V 60-Cycle applications. They are not calibrated for proper trip performance in 230V 50 Hz systems as found in Europe, Australia or New Zealand.
For further information see these technical briefs
AC Ground Faults, the Boater, and ABYC Understanding Equipment Leakage Circuit Interrupters (ELCIs) and Ground Fault Circuit Interrupters (GFCIs) to make your boat safer.